Bob is not working with pgx array types

[hiendaovinh]

Hi, I was trying to use bob with pgx. When I try to fetch items from QueryContext it gave me this error

pq: unable to parse array; expected '{' at offset 0

I believe this is a problem with scanner. Please take a look.

type BobExecutor interface {
	QueryContext(ctx context.Context, query string, args ...any) (scan.Rows, error)
	ExecContext(context.Context, string, ...any) (sql.Result, error)
}

type PGXPool interface {
	Begin(ctx context.Context) (pgx.Tx, error)
	Exec(ctx context.Context, sql string, arguments ...any) (pgconn.CommandTag, error)
	Query(ctx context.Context, sql string, args ...interface{}) (pgx.Rows, error)
	SendBatch(ctx context.Context, b *pgx.Batch) pgx.BatchResults
}

type BobExecutorPgx struct {
	pool PGXPool
}

type rows struct {
	pgx.Rows
}

func (r rows) Close() error {
	r.Rows.Close()
	return nil
}

func (r rows) Columns() ([]string, error) {
	fields := r.FieldDescriptions()
	cols := make([]string, len(fields))

	for i, field := range fields {
		cols[i] = field.Name
	}

	return cols, nil
}

func (v *BobExecutorPgx) QueryContext(ctx context.Context, query string, args ...any) (scan.Rows, error) {
	r, err := v.pool.Query(ctx, query, args...)
	if err != nil {
		return nil, err
	}

	return rows{r}, nil
}

func (v *BobExecutorPgx) ExecContext(ctx context.Context, query string, args ...any) (sql.Result, error) {
	tag, err := v.pool.Exec(ctx, query, args...)
	if err != nil {
		return nil, err
	}

	return driver.RowsAffected(tag.RowsAffected()), err
}

[stephenafamo]

My immediate guess is that this is happening because the array types in pgx do not implement sql.Scanner.

If using github.com/stephenafamo/scan directly, it is possible to add the custom pgx types using WithScannableTypes. However, the code generated by Bob does not account for this.

[hiendaovinh]

I believe this will be fixed soon.

Ref:
golang/go#67546
jackc/pgx#2029
jackc/pgx#1779

[stephenafamo]

That would make a lot of things simpler 👍🏾